eth2 Posted May 23, 2014 Share Posted May 23, 2014 I have my VAC at the manufacturer's currently. It had a problem with a "run away tube" which caused damage to the sockets. It has now been repaired and upgraded. They asked if I wanted a "guardian circuit" installed that would shut down the amp if there was another such incident. The cost is $500. Should I do it? Quote Link to comment Share on other sites More sharing options...
seti Posted May 23, 2014 Share Posted May 23, 2014 That is costly. I've never had a runaway tube. Has this been an ongoing issue? Quote Link to comment Share on other sites More sharing options...
beeker Posted May 23, 2014 Share Posted May 23, 2014 sounds like bs...man earl i would darn near sell you a killer tube amp myself, integrated thats loud, or quiet and has absolute minimal noise at pause or volume down for about 500....Pass on this feature my gawsh...sounds like your getting the run around! 1 Quote Link to comment Share on other sites More sharing options...
eth2 Posted May 23, 2014 Author Share Posted May 23, 2014 That is costly. I've never had a runaway tube. Has this been an ongoing issue? No, but I am new to tube amps Quote Link to comment Share on other sites More sharing options...
joessportster Posted May 23, 2014 Share Posted May 23, 2014 Not sure the value of your amp / amps, If it were me I would search out other Vac amps and see if the add on is typical and also see if it looks to add to amps value Generally I would say this is not an area for concern, as a tube amp should never be operated unless you are there listening, if a tube is failing you will hear odd harmonics and distortion first in almost all situations. Of course when you hear this the idea is to rush over and shut it off B-4 the tube runs away and causes damage If I found I could recoup the investment on resale I would say "what the hell" and have it installed (ounce of prevention is worth a pound of cure) I personally am Happy you have posted the numerous issues you have had with those amps (helps me steer clear) I am not happy you have issues just happy you share the info 3 Quote Link to comment Share on other sites More sharing options...
eth2 Posted May 23, 2014 Author Share Posted May 23, 2014 Not sure the value of your amp / amps, If it were me I would search out other Vac amps and see if the add on is typical and also see if it looks to add to amps value Generally I would say this is not an area for concern, as a tube amp should never be operated unless you are there listening, if a tube is failing you will hear odd harmonics and distortion first in almost all situations. Of course when you hear this the idea is to rush over and shut it off B-4 the tube runs away and causes damage If I found I could recoup the investment on resale I would say "what the hell" and have it installed (ounce of prevention is worth a pound of cure) I personally am Happy you have posted the numerous issues you have had with those amps (helps me steer clear) I am not happy you have issues just happy you share the info Always glad to act as the sacrificial lamb for my friends! 2 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 23, 2014 Share Posted May 23, 2014 OK ,I'll be the stupid one. what exactly is a "run away tube"? Quote Link to comment Share on other sites More sharing options...
joessportster Posted May 23, 2014 Share Posted May 23, 2014 A tube that gets hot and the pins loosen Just enough for the tube to eject itself and it then runs off SHEESE I thought everyone knew this one 1 Quote Link to comment Share on other sites More sharing options...
wvu80 Posted May 23, 2014 Share Posted May 23, 2014 OK ,I'll be the stupid one. what exactly is a "run away tube"? I didn't know either, so I Google'd it. The search had this (Earl's) thread at the top of the results. 1 Quote Link to comment Share on other sites More sharing options...
beeker Posted May 23, 2014 Share Posted May 23, 2014 The search had this (Earl's) thread at the top of the results. I bet vac reads it and figures shoot...you win some ya lose some lol I hope they dont get you on this one earl... I will say though if you dont i bet it happens...vac sound like a bunch of slimeballs Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 23, 2014 Share Posted May 23, 2014 (edited) Maybe THIS? Basically, excessive heat leads to increased current flow, which causes more heat, leading to more current flow, etc. Edited May 23, 2014 by CECAA850 Quote Link to comment Share on other sites More sharing options...
eth2 Posted May 23, 2014 Author Share Posted May 23, 2014 Yes, the electrical engineering description. My understanding is that when the tube gets gassy, it begins to draw more power causing an imbalance among the tubes, and accelerating the heat rise in the defective tube until it fails. On its way to failure it can draw so much power that it destroys the components in its path. But then again what do know? I was gong to pay $500 for a protection circuit. Quote Link to comment Share on other sites More sharing options...
beeker Posted May 23, 2014 Share Posted May 23, 2014 Maybe THIS? That must be....It sounds like their just soaking Earl... Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 23, 2014 Share Posted May 23, 2014 My understanding is that when the tube gets gassy, it begins to draw more power They just need to install a fart valve. Quote Link to comment Share on other sites More sharing options...
eth2 Posted May 23, 2014 Author Share Posted May 23, 2014 My understanding is that when the tube gets gassy, it begins to draw more power They just need to install a fart valve. We don't need no stinkin' "fart valve." Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 23, 2014 Share Posted May 23, 2014 My understanding is that when the tube gets gassy, it begins to draw more power They just need to install a fart valve. We don't need no stinkin' "fart valve." Well, it's your amp.. Don't say I didn't try to help. Quote Link to comment Share on other sites More sharing options...
beeker Posted May 23, 2014 Share Posted May 23, 2014 Is this another one of your joke threads??? idk man sounds like vac is hungry! Quote Link to comment Share on other sites More sharing options...
USNRET Posted May 23, 2014 Share Posted May 23, 2014 I have experienced thermal runaway in NiCad aircraft batteries; don't want to be around that...or fart valves Quote Link to comment Share on other sites More sharing options...
eth2 Posted May 23, 2014 Author Share Posted May 23, 2014 Is this another one of your joke threads??? idk man sounds like vac is hungry! No joke. Apparently VAC's new amps have this protection circuit. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 23, 2014 Share Posted May 23, 2014 Apparently VAC's new amps have this protection circuit. That was going to be my next question. If they're aware of the issue, has it been corrected in production? Quote Link to comment Share on other sites More sharing options...
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